Retinal detachment (RD) is one of the most common ophthalmologic emergencies and frequently leads to irreversible damage to vision. When rapid access to repair surgery is available, sight is generally preserved, although up to 40% suffer permanent loss of visual acuity. In large parts of the world without access to advanced medical care, blindness often results. Until recently, the major known risk factors were not very useful in prevention: advancing age, myopia and cataract surgery all increase the risk of RD. Only a minority of RD cases was currently thought to be preventable - those caused by acute eye trauma and by diabetes. In 2008, a member of our research team published the first epidemiologic study identifying a strong association between occupational exposure to heavy lifting and risk of RD: the odds ratio of RD was approximately 4 for those reporting a history of heavy lifting compared to no heavy lifting. This first study used a simple measure of lifetime heavy lifting and now a more detailed exposure assessment for a larger population is needed to further evaluate the results. Experimental and clinical evidence for the biologic plausibility of tis association exists and can be used for a biologically-based exposure assessment. If the lifting - RD association is confirmed in a larger study, heavy lifting could explain a substantial fraction o the risk of RD in working adults. The first study also reported a strong association between obesity and risk of RD, a finding with enormous potential public health impact which will be further investigated in the proposed study. The objective of the proposed study is to evaluate the risk of RD from lifting and related manual materials handling (MMH) exposures by conducting a large case control study of incident cases of retinal detachment. We propose a pathophysiologic mechanism linking physical effort to RD which suggests a hierarchy of testable hypotheses about the timing of exposures and the likely forms of exposure metrics. This proposal has the following specific aims: Aim 1: Develop metrics of occupational exposures to lifting that will enable epidemiologic evaluation of alternative biologic hypotheses of the association with RD. Aim 2: Measure the associations between alternative metrics of lifting and related MMH tasks and RD in a case control study [using telephone interviews]. The role of obesity, including as a modifier of the effect of heavy lifting, will also be studied. The finding of this study will be useful in guiding translational research to develop new prevention strategies for RD. Heavy lifting and related MMH tasks are very common hazards in nearly all the NIOSH NORA industry sectors. [The NIOSH NORA Sector Councils that have prioritized MMH will be consulted to disseminate these findings and apply them in existing MMH risk prevention programs].